Level



Patented Mal'. 19, 1929.V

- 1,705,889 ,PATENT orrigcs.

ROBERT H. BERTRAll/l'., DAVENPORT, IOWA.

LEVEL- Application filed November` 11, 1925. Serial No. 68,427.

This invention relates to improvements in leveling apparatus and has for its prime cbject to provide a level of very sensitive construction and designed to accurately indicate the angular inclination of objects upon which it is placed. J

A further object of the invention is the provision of av level of the above character having a graduated dial so as to designate the exact angular inclination of an object from a level yor horizontal position.

A still further objectof the invention isV tlie'provision of a leveling apparatus of lcom pact and durable construction and designed so as to be sold at a reasonable cost.

Other objects and advantages of this invention will become apparent as the description progresses.

In the accompanying` drawing forming a part of this specification and in which like numerals are employed .to designate corresponding partsthroughout the same:

Figure 1V is a front elevation of a fragmentary portion of a level constructed in accordance with my invention,

Figure 2 is a longitudinal sectional view showing the casing structure in elevation,

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure 1, n

Figure 4L is a detail perspective view of a member forming a part of an indicating mechanism, and l Figure 5 is a similar view of a complementary member also forming a part of the indicating mechanism. y. i I I '1n thev drawing, wherein is illustrated a preferred embodiment of theinvention, the numeral 10 generally kdesignates the body or stoclr of the level. This stock is usually of rectangular formation and preferably constructed ofwood or light metal. One or both of the longitudinal edges of the stock are straight edges so that the apparatus may accurately indicate the angular position 'of Securely mounted in the chamber 11 formedv in the stock 10 is an annular 4casing 13 designed to provide an enlarged ring 141 at its upper portion of substantially" increasedv di-A ameter. lThe structureof the casing is narranged so as to snugly fit the counter-sunk chamber formed in the stock and is retained securely inposition therein by means of a pair of oppositely disposed ears 15 apertured for the reception of'suitable fastening screws 16. Formed at the center of the casing and projecting outwardly is a bearing sleeve 17 of comparatively small diameter, this sleeve being enclosed at its outer extremity and adapted to lit flush with the rear side of the stock. The forward edge of the casing is arranged so as tobe fitted flush with the front side of the stock, the ears 15 being positioned in suitable recesses for this purpose.

Rotatably mounted in the casing and arranged so as to be freely rotatable therein is an indicating mechanism composed of a rpairof co-acting relatively vmovable members. One of the indicating members comprises a tapered frame structure 18 provided at the outer enlarged end with apair of arcuately formed bars 19, spaced to provide a slot 20 therebetween. The inner reduced end ofthis frame structure is formed with an adjustable tube 21 of arcuate formation, the outer' edge of this tube being split andprovided withcoacting parallel ears 22. vThefbottoinear is provided with an internally screw threaded opening, while the upper ear is provided with a smooth bore of circular formation. This structure permits the connection of a/screw 23 adapted to project through the openings vformed in the ears 22 for adjustable connection of the sleeve, the purpose of which will become apparent as the .description progresses. rlhe taperedbody ofthe frame 18 connects with the sleeve 21 by means of V-shaped ribs 24'extending on they upper and lower f edges of the sleeve and preferably formed integral therewith; The opposite'extremity of the frame 18 is provided with an outwardly Vnation of the level, as will be described more lfully hereinafter.

frame 18 and arranged so as to provide a highly sensitive indicating apparatus, is a rotatable balance member 26 vembodying' at one end a. substantially Ueshaped bracket'27 having the upper and lower parallel projections of tapered formation asat 28 to provide fulcrum points 28h. A longitudinalbar 29 eX- tends laterally from the U-shaped bracket 27 and carries on Vits outer extreme end a right angular projectionin .the form ofa circular guide pin 30, this member being detachably Mounted in co-acting relation with they llO secured to the end of the bar by aset screw or in any suitable manner, It Will be noted, from Figure 5 of the-drawing, that the lower projection of the movable indicating member is provided with a laterally extending pivot pin 31 of preferably circular formation and adapted to rotatably engage the bearii'ig Sleeve 17 formed in the casing structure. rlhe members 18 and 26 are assembled by placing the fulcrum points 28" at the apex of the V-shaped ribs 24 formed on the sleeve 2l. The guide pin 30 is then positioned in the arcuate slot 19 and securely fasten-ed to the-eX- teiision bar 29 of the member 26. 'll his connection provides a delicate balance connection of the movable indicating structure, the pivot pin Blbeing rotatably mounted in the bearing sleeve 17 so that the indicator will be readily rotatable and at the same time properly balanced.

ln order that the pointer 25 may accurately indicate the inclination of the level a tube 32 of arcuate formation is secured in the adjustable sleeve 21, this tube being constructed of glass or metal and adapted to contain a suitable liquid,'preferably a solution of mercury and alcohol. The tube is preferably arranged -in a radial arc With the indicating pointer so as to effectively balance the frame 18.

An important characteristic of the present invention embodies the provision of a dial 32 to be formed on the outwardly directed flange or shoulder ring 14.-, this dial being preferably of circular formation and graduated into degrees of angular measurement. lNit-h particular reference to Figure 1, it Will be seen, that the zero mark on the dialis at the lowest point on the transverse center line through the level mechanism, and the dial is formed With numerals at regular intervals indicating the number of degrees of angular measurement.

In use, the lower longitudinal edge of the level is placed upon the object Whose angular inclination it is desired to ascertain and the position of the level stock and casing determined relative to that of the pointer 25. From the foregoing description, itis obvious, that the pointer 25 Will be at all times retained in a downward vertically aligned position with the pivot pin. The inclined position of the casing will, therefore, accurately indicate the exact angle of inclination of the surface upon which the level is positioned. The piovision of the independently movable indicating structure necessarily forms a delicately balanced pointer designed to indicate the angularl measurement to a very accurate degree. The sensitiveness of the indicating apparatus is further increased by the provision of the arcuate liquid tube 32, filled with a mercury solution, and thus having a gravitational effect to balance the pointer. lt is therefore apparent that the indicating mechanism ivill be normally held in a verticallv suspended position by the attraction of gravity, While the body of the level may ascasing,

sinne various angular positions from a horizontal to a vertical angle.

The upper edge of the casing 1B is provided with an interiorslioulder of annular formation adapted to receive thereon a cover 33 removably mounted on the casing and preferably constructed of glass oi other transparent material. yllhis cover is rigidly' retained in position by a resilient metallic ring Se adapted to be contracted so asto engage an annular groove formed adjacent the upper edge of the casing and prevent displacement of the cover 33. f

rlhis structure provides a durable level of compact structure designed particularly to provide an accurate indicating apparatus of extreme accuracy arranged so as to readily indicate the angular inclination from al level or horizontal position.

lt is to be understood that the form of my invention herewith shown and described is to be taken as the pre'ferred example of the saine and that various changes as to the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described my invention, l cl aim: i

1. ln apparatus of the character described coii'iprising a body having a chamber formed therein, a gravity actuating mechanism mounted in the body including a tapered frame member having an adjustable vsleeve formed on one end and an arcuate slot formed adjacent the opposite end thereof, a pointer formed on the outer extremity of the frame, a co-acting balance member embodying a U- shaped bracket having a pivot pin formed laterally on one projection thereof adapted to pivotally support the frame member, a longitudinal arm formed integral With the bracket and extending laterally therefrom, a guide pin secured to the out-er extremity of the arm adapted to engage the arcuate slot formed in the frame member, and a liquid containing tube secured in position in the sleeve formed on the frame member so as to sensitively balance the gravity actuated mechanism. A 4

2. A level comprising a` stock having a counter-sunk chamber in the center thereof, a casing having an enlarged ring adjacent the outer edge securely mounted in the chamber, a bearing sleeve formed in the center. of the indicating mechanism'y pivotally mounted in the casing including a tapered frame having an adjustable sleeve formed on one end thereof and an arcuate slot formed adjacent the opposite end of the frame, a pointer formed adjacent the arcuate slot, a co-acting balance member including a U- shaped bracket, a longitudinal bar extending transversely from the bracket, a guide pin secured. on the opposite end of the bar, the said frame being pivotally mounted on the balance member -to provide an accurately balanced indicating mechanism, a pivot pin formed on the balance member engageable With the bearing sleeve formed in the casing, a tube containing liquid secured in the adjustable sleeve so as to balance the frame member, a circular dial formed in the casing graduated to indicate degrees of langular measurement, the dial being arranged in the path of movement of the pointer, and a cover of transparent material removably secured on the casing for enclosing the same.

3. A level indicator of the character described, comprising a balance member including a` bar formed at one end'to provide a cradle, a laterally projecting supporting pivot pin at one side of said cradle, a ful crum point on each side of said cradle, a swinging member provided With a pair of bearings each receiving one of said `'ulcrum points, a pointer carried by said swinging member, means carried by said` bar and en* gaging said swinging member for limiting its movementand a balance Weight carried by said cradle, an open tapered frame formed` to provide a guide slot at 011e side thereof, a pair of substantially inverted V-shaped bearings adjacentthe tapered end of the frame each designed to receive one of said i'ulcrum Y points to set up a knife bearing between the frame and the balance member, a retaining pin carried by said bar and engaging in said guide slot, a pointer carried by said frame, an arcuate tube and means for ksecuring the tube to said frame.

In testimony whereof I aflix my signature.

ROBERT H. BERTRAM. 

